Freewheeling mechanism of motor



A, 9, 1938. K, MAYBACH R15 20,824

FREEWHEELING MECHANISM 6F MOTOR CARS Original Filed June 20, 1933Reissued Aug. 9, 193a rnsawmaanmo rgg msm or Moron Kai-1 Maybach,Frledrichshafen, Bodensce. Germany, assignor to Maybach-Motorenbau G. m.b. 11., Frledrlchshafen, Germany Original No. 2,034,263, dated March 17,1936, Se-

rial No. 676,633, June 20, 1933. Application for reissue September 26,1936, Serial No. 102,681. In Germany July 1. 1932 v 1: Claims. (01.lea-m) My invention relates to motor cars in which;

means are provided for temporarily disconnecting the motor from thedriving wheels for the purpose of free-wheeling, especially when driving5 on level roads or down hill. During such periods the speed bL themotor is automatically reduced to the lowestpossible minimum. so thatthe fuel ,consumption is also a minimum, and at the same time theworking of the motor should be practically noiseless.

Generally there are auxiliary machines, such as dynamos and others,driven by the motor.

Some of these machines serve for feeding energy,

to storage elements, such as electric accumula 5 tors or accumulatorsfor compressed air, or the like. During the free-wheeling periods of themotor car, when the motor runs with reduced speed, the amount of energyfed to the accumulators is also lower than during the time the motor isrunning at normal speed. Consequently the accumulators may in certaincases run short of energy, especially when the driver of the car hasbeen free-wheeling for long periods. To avoid the very disagreeableconsequences of *such 25 running short of energy necessary for certainpurposes and in cases of emergency, it has been suggested to providemore powerful auxiliary machines for feeding the accumulators. But suchmore powerful machines are also larger, 30 heavier and more expensive,so that many disadvantages are connected therewith.

My invention gives a very simple yet effective solution for theseconditions. I provide means which automatically alter the speed limit ofthe 35 motor when disconnected to a higher limit for the periods duringwhich the car runs faster than a certain minimum speed, that is for theperiod during which energy from the accumulators may he wanted. Thus.during the freewheeling periods the motor has the lowest possible speedas long as the disconnected car in its speed runs below a certain limit,but as soon as the car exceeds this limit automaticall a higher speed isset for the disconnected motor.

45 Consequently, during this latter period the auxil- In other words,when the control means for the motor when disconnected, working independency of the motoritself, whichcauses the motor to run with aconstant low speed. Then I have a second speed control means working independency of the speed of 5 the car; this second means does not controlthe speed of the motor directly, but simply acts on the first controlmeans in such manner that the automatically controlled motor speed israised to 1 another levelas soon as the car inits speed q exceeds apredeterminedlimit.

All this willbe understood best when having reference to, the drawingwhich represents an example embodying my invention.

The flgure is-a mere diagram showing invertical section the mainelements of the mechanism.

The motor is indicated at M. Its crank shaft I by means of flexibleshaft 2 drives the .fluid pump 3. Shaft I on the other side of frictionclutch 21, 28 and in driving connection with the change speed gear andthe driving wheels of the car (both not represented) by means-offlexible shaft 5 drives fluid pump 8.

Pump 3 sucks out of well I! and forces the fluid, oil for instance, intospace I. There is an opening I controlled by screw 0 by means of whichit is possible to determine the liquid pressure within space 'I whichshall acton control member 39 sliding within cylinder 49 and being underthe reaction of spring ll. Tube 23 com- 30 ing from the intake manifoldof the motor M' connects to cylinder is and is adapted to create vacuum(from the intake manifold) within tube ll whenevercontrol member 39 ismoved downward; whereas upward movement of member 39 connects tube IIwith the open air by means of opening I 2 in cylinder 49. Thus, control'member 88 in accordance with the pressure prevailing in space I andfollowing the slightest changes inthis pressure connects tube ll eitherwith the 40 vacuum of manifold 24- or with the open air of aperture 12,or, when the pressure in space 1 and that of spring "I are equal itrests in its middle position. I

Tube I l is connected to cylinder l3 in'which 5 piston II is adapted tomove up and down. One end of cylinder II is connected to the open air,whereas on the other side of piston ll the vacuum of tube ll may actagainst the reaction of spring I. Consequently, whenever tube II isconnected to the vacuum of manifold 24 piston It moves upward so thatpiston r l6 pushes against lever l1 and thereby o s throttle ll.

D p I decreases'in revolutions so that the pressure in space 1 goes 5.

open throttle ll so that the motor, and with it pump 3, increases inspeed again.

speed. which depends upon the setting of screws 0 and the features ofspring l0. 8 ws l3 and II" serve for limiting the stroke of I: ll.

Oi course, throttle ll .can besid be moved at will by the driver bymeans of lever 20, rod 2| and lever 22, against the action of spring is.Pump 6, driven by shaft 4, in its speed depends upon the speed of thecar. As long as the friction clutch 21, 2. is in engagement, both pumps,I and 6, rotate at equal speed; but when the car is de-clutched, forexample by pushing down lever I or by means of vacuum as indicated at2!, and when the'gas pedal is released, the motor automaticallydecreases in speed and comes to a constant low speed as explained above,

but pump 6 at the same time in its speed depends upon the speed of thecar,,which may be comparatively higher depending upon the roadconditions,

Pump 6 sucks out of space 32 which is in connection with well by meansof aperture 3i Y controlled by screw Ill. Consequently, pump 8 whenexceeding in speed a certain limit, which is controlled by setting screw30, causes a certain decrease in pressure within space 32 therebyopening valve 31 against the reaction of spring 34 and also against thereaction of the liquid pressure within space I, because of valve 31 andconnecting rod 36. The opening of valve 31 toautomatically controlledlowest motor speed.

vlBy means of screw the vehicle speed is set,

; at which the automatically controlled motor speed changesautomatically. And the new higher automatically controlled motor speedis determined by adequately setting screw 38.

The first mentioned motor speed should be as low as circumstances allow.The speed limit for the car at which the automatically controlled vmotor speed is altered may for example be at about 20 miles per hour.And the upper automatically controlled motor speed should be chosen inaccordance with the prevailing conditions in every case.

I do not want to be limited to the details described or shown in theexample, as many variations will occur to those skilled in the art.

What I claim is: 1. In a motor driven vehicle mechanism of the typedescribed comprising: a member rotating independency of the motor speed,a member rotating in dependency of the car speed, a member v Thus, themotor, if left to itself. will come to a constant trolled idling speedof the motor to a higher limit as soon as the car speed exceeds apredetermined limit.

2.'In a motor driven vehicle in combination;

a first fluid pump driven. by the motor, a second fluid pump, driven bythe car, a member for automatically controlling the fuel intake oithemotor, means for operating said member, said operating means beingcontrolled by the pressure of the liquid pumped by said first pump, anda valve controlled by said second pump, said valve being adapted toalter the pressure of the liquid pumped by said first pump.

3. In a motor driven vehicle in combination the elements as claimed inclaim 1, and further including: means for setting the automaticallycontrolled low speed for themotor, means for setting the automaticallycontrolled higher speed for the motor," and means for setting the carspeed at which the automatically controlled motor speed is to change.

4. In a motor driven vehicle mechanism of the type described comprising:automatic speed controlling means for the motor causing a certain lowidling speed and a device for temporarily raising saididling speed limitto a higher but constant level, said latter device working in de-'pendency of the car speed.

5. In a motor driven vehicle in combination: a first fluid pump drivenby the motor, a second fluid pump driven by the car, a fluid pressuremotor, a valve for controlling the pressure in said fluid pressuremotor, said valve being influenced by the pressure of the liquid pumpedby said first pump, a member for automatically controlling the fuelintake of the motor for driving the vehicle, said member being operatedby said fluid pressure motor, and means adapted to alter the pressure ofthe liquid pumped by said first pump, said means being controlled bysaid second pump.' v

6. In a motor driven vehicle mechanism of the type described, meanscausing the motor when declutched to 11111 at a low idling speed as longas the vehicle speed does not exceed a predetermined limit, and meansworking in dependency on the vehicle speed and becoming automaticallyoperative when at any time while the motor is declutched the vehiclespeed is above the predeetgdrmined limit to increase the'motor idling sp7. A motor drivenvehicle speed control mechanism operative duringperiods when the vehicle is in free-wheeling, and including, means'forcausing the motor to run at a low idling speed, and a speed regulatingdevice working in dependency on the vehicle speed operative to raise theidling speed of the motor when the vehicle speed increases, andoperative to lower the idling speed of the motor when the vehicle speeddecreases.

8. In a motor driven vehicle mechanism of the type described, means forsetting the motor to run at a low idling speed, and a device becomingoperative upon declutching of the motor and working in dependency onvariations in the vehicle speed at any time during periods when thevehicle is free-wheeling to change the idling speed of the motor.

for varying motor speed between low and high idling rates, saidregulating mechanism becoming operative when the motor is declutched andthe minimum idling rate until the car speed is decreased to apredetermined limit.

11. The combination in a motor car of a. clutch,

a vehicle power shaft driven by the motor through the clutch, andregulating mechanism for the motor fuel supply working in dependency onthe speed of said shaft during periods when the shaft is declutched andthe vehicle and said shaft overrun the motor, said regulating mecha- 1nism becoming operative when the speed difference between the shaft andmotor is increased by the Year running faster to raise the idling speedof the motor, and operating when the overrunning shaft is reduced inspeed by the car running slower to decrease the idling speed of themotor.

12. The combination with a motor car of regulating mechanism for themotor fuel supply working in dependency on the speed of the vehicle,

said mechanism becoming operative when the car speed is over apredetermined limit at any time during free-wheeling periods when themotor is declutched to cause the motor to run faster than the minimumidling rate.

13. The combination in a motor car of a clutch, a vehicle power shaftdriven by the motor through the clutch, and regulating mechanism for themotor fuel supply working in dependency on the speed of said shaftduring periods when the shaft is declutched and overruns the motor, saidregulating mechanism operating when the speed difference between theshaft and motor is over a predetermined limit to cause the motor to runat a speed above the minimum motor idling speed, and operating when thespeed difference between the shaft and motor is reduced below saidpredetermined limit to reduce the speed of the motor.

KAIRL MAYBACH.

